System of electric metering.



PATENTED JUNE 2, 1903.

E. THOMSON. SYSTEM OF ELECTRIC METERING.

APPLICATION FILED MAR. 21, 1898.

N0 MODEL UNITED STATES IPatented J'une 2, 1903.

PAT NT O FICE.

EIIII'III THOMSON, OF SWAMPSOOTT, MASSACHUSETTS, ASSIGNOR TO THE GENERALELECTRIC COMPANY, A CORPORATION NEW YORK.

SYSTEM OF ELECTRIC METERING.

SPECIFICATION forming part of Letters Patent No. 729,811, dated June 2,1903.

Application filed March 21, 1898.

To all whom it may concern:

Be it known that I, ELIHU THOMSON, a citizen of the United States,residing at Swampscott, in the county of Essex, State of Massachusetts,have invented certain new and use ful Improvements in Systems ofElectric Metering, of which the following is a specification.

In order to render certain types of electric meters positive in theiraction, it is customary to provide them with a potential-coil throughwhich a certain amount of current passes and to mount this coil withinthe influence of afieldmagnet the strength of which varies with the loadon the system to be metered. In the majority of meters thispotential-coil is permanently connected in circuit and the currentflowing through this coil represents a certain loss of energy. This lossmay when the load on the system at the point of consumption is lightrepresent a considerable fraction of the total energy supplied to theconsumer. This is particularly noticeable where the consumer requirescurrent for a few hours each day and then has only a small number oftranslating devices in circuit.

My invention has for one of its objects to increase the efficiency ofthe meter by reducing the loss of current due to the potentialcoil, atthe same time preserving the accuracy of the meter registration. Toaccomplish this, the circuits of the meter are arranged in such mannerthat current instead of being permitted to flow through thepotential-coil at all times is restricted to certain definite intervals.The intervals in which current is permitted to flow in thepotential-coil may bear any desired relation to the intervals in whichthe circuit is interrupted. For example, the current maybe cut off fornine-tenths of the time and permitted to flow during the remainingtenth, in which case the meters will register with sufficient accuracy;but their registry will only be about one-tenth what it would have beenif current had been flowing all the time. If the intervals of making andbreaking the circuit are not too great, the meter-readings will beaccurately proportional to the energy consumed, and by properlyadjusting the registering mechanism the Serial No. 674,606. (No model.)

increase or decrease of current consumption by the translating devices.terrupter by which I effect this result comprises novel features andconsists of an electrically-actuated device controlling a snapswitch, bywhich a quick break of the circuit is effected and a long range ofmovement given to prevent interference from arcing. The operation of thesnap-switch is controlled by a vibratory device electrically operated inone direction and provided with a damping mechanism for slowly returningit to the point where electrical influence can again be exerted. i

The novel features of the invention will be more particularlyhereinafter described, and will be definitely indicated in the claimsappended to this description.

In the accompanying drawings, which illustrate my invention, Figure l isa diagram of a metering system embodying my improvements, including myimproved current-interrupter for the potential-circuit. Fig. 2 is a sideelevation of the current-interrupter.

D and D represent a supply-circuit leading from the supply-generator D,and D D represent the leads to a consumers premises, including a groupof lamps L or other current-consuming devices.

I have shown my invention as applied to a type of meter such asthewell-known Thomson recording-wattmeter, though, as will be evident tothose familiar with the art,;fit may be employed with "other types ofmeter.

As shown in the diagram, in series relation to the translating devicesare the currentcoils of the meter, forming a field within which'rotatesan'armature K, geared to the counter, said armature being included in aactual energy consumed may be indicated. I 1 potential shunt across themains, including The current-ina resistance R and the coils of thearmature K, to which current is led through a commutator, as indicated.A damping-disk K on the armature-shaft, mounted in the usual manner,slows down the speed of the armature. In the potential-circuit in whichthe armature is included I place the operatingcoils V V of my improvedinterrupter. These are so connected that when current passes the coilswill mutually repel each other. The coil V is mounted on a bar supportedon a knife-bearingj, the free end J swinging between the poles of apermanent magnet X.

Supported on a standard I by means of a knife-bearing, as indicated atg, is a sector WV, the upper face of which is of insulating material andinto which is set a short contact-segment S, or, if desired, the entiresector may be made of insulating material except the contact S and thebearing. This sector is placed between two stops it, mounted on arms orbrackets secured to the standard. A metallic contact-springB is mountedso as to bear against the upper face of the sector and is connected by awire 6 with one side of the potential-circuit. The contact S connects bya flexible conductor with one terminal of the coil V the other terminalof said coil being in electrical connection with a terminal of the coilV, the other terminal of which connects with one of the brushes of thecommutator of the meter-motor. The rocking lever J carries an arm J towhich is connected a coil-spring Y, the other end of which is secured toa pin mounted on the sector W, the points of connection being so chosenthat the movements of the lever J, under the influence of the mutualrepulsion of the coils in one direction and of gravity or a spring inthe opposite direction, will shift the axial line of the coil-spring Yon one side or the other of the knife-bearing g.

As shown in the drawings, the parts are in a position where gravity hasjust effected the return of the coil V and the arm .I has been justshifted so as to bring the center line of the spring beyond theknife-bearing to the left. The parts are therefore in a position to drawthe sector \V to the left and close the circuit when the sector willoccupy the position shown in dot. A potentialcircuit will then be madethrough the armature of the meter-motor and through the coils V Venergizing the latter and effecting the repulsion of the coil V therebyshifting the arm J to the right until the axial line of the springpasses the knife-bearing, when the sector will be snapped to the right,thereby opening the circuit and quickly separating the contacts 13 andS. The lever will then settle under the preponderating weight of thecoil V and slowly, by reason of the damping action of the magnet X, tothe position shown in the drawings, when the cycle of operations justtraced will be repeated. Thus it will. be seen that the circuit of thepotential-coil of the armature is closed only for a part of the time,

(While the contacts B and S are in engagement,) during which time themeter will register. At all other times the potential-circuit of themeter is open and registration is not effected. Obviously the relativelength of time during which the potential-coil of the meter is incircuit and out depends upon the preponderating effect of the coil V andthe damping action of the magnet X and can be adjusted through aconsiderable range, which may be varied by giving the sector agreater orless play between its arresting-stops, by altering the relation of thedamper X and the preponderating weight of the coil V and by changing theposition of the arm J with re lation to the knife-bearing. Thus thereresults a continuous slow vibration of the lever J and a periodicinterruption of the armature-circuit, reducing the amount of energyconsumed thereby.

While I have shown and described my interrupter in connection with anelectric metering device, it will of course be understood that it may beapplied to other purposes where a slow and definite periodicinterruption of an electric circuit is desired.

What I claim is 1. In an electric metering system, the combination of aconsumption-circuit, a metermotor controlled thereby, and anelectricallyoperated current-interrupter controlling the meter-motor andclosing it at regularly-re curring intervals during operation of atranslating device in said consumption-circuit.

2. In an electric metering system, the combination of aconsumption-circuit, and a meter-motor controlled thereby, one of the operative circuits of the motor including an electricallyoperatedcurrent-interrupterclosing the circuit at regularly-recurringintervals during the operation of a translating de-' vice in saidconsumption-circuit.

3. In an electric metering system, the combination of aconsumption-circuit, a metermotor having one circuit in series with atranslating device, apotential-circuit on the motor, and anelectrically-operated current-interrupter in the potential-circuitopening it intermittently during consumption of current in the circuit.

4. In an electric metering system, the combination of aconsumption-circuit, a metermotor having one circuit in series with thetranslating devices, a potential-circuit on the motor, and anelectrically-operated currentinterrupter in the potential-circuit,adjusted to hold the circuit open for longer intervals than closed.

5. An automatic current-interrupter, com prising contacts, means foropening and closing the same, and a magnetic damper to effeet a slowmovement.

6. An automatic current-interrupter comprising contacts, an electricvibrator, and a magnetic damper for slowing its movements.

7. An automatic current-interrupter comprising contacts, a vibrator foropening and closing the same, electric controlling devices for movingthe vibrator in one direction, means for slowly returning it, and adamper for slowing the movements of the vibrator.

8. An automatic current-interrupter comprising an electrically-operatedvibrator, a snap-switch operated thereby at each movement of thevibrator, and a magnetic damper to retard the vibrator movements.

9. An automatic current-interrupter, comprising a rocking contact, aspring connected thereto, and a coil to shift the axis of the spring toopposite sides of the pivotal point of the contact.

10. An automatic current-interrupter for intermittently opening andclosing a circuit, comprising a movable contact, a coil for quicklyopening the contact, a counterbal anced lever for slowly closing thecontact, and a magnetic damper for slowing the movement of the lever.

11. The combination of stationary fieldcoils through which the whole ora portion of the current to be measured passes, an armature mounted forrotary movement with re-- spect to the field-coils and influenced by thepotential of the system, the coils and armature uniting to form a singlemetering device, and automatic means controlled by the current flowingin the system, but uninfluenced by the meter, for interrupting thearmaturecircuit at predetermined recurring intervals during the flow ofcurrent to be measured.

12. In an electric measuring instrument, the combination of afield-magnet, a single armature mounted for movement with respect to thefield-magnet, and an automatic electromagnetically-aetuatedcircuit-breaker separate from the meter for periodically opening andclosing the armature-circuit at regularlyrecurring intervals during theflow of current to be measured.

13. In an electric measuring instrument, the combination of afield-magnet, an armature mounted for movement with respect to thefield-magnet, a circuit-breaker independent of the meter parts,comprising a fixed and a moving coil, and a switch actuated by themoving coil.

14. In a circuit-breaker for an electric meter, the combination of astationary coil, a moving coil so related to the stationary coil as tobe affected by current flowing therein, damping mechanism, and a switchactuated by the moving coil; the arrangement being such that the circuitof the meter is interrupted at predetermined intervals, independent ofthe amount of current flowing in the system.

15. In a circuit-breaker, the combination of a stationary coil, a movingcoil connected in circuit therewith, a pivoted lever carrying the coilat one end and a damping device at the other, a pivoted switch-piece,and a spring controlled by the moving coil for actuating theswitch-piece.

16. In an automatic circuit-breaker for opening and closing a circuit,the combination of a fixed and a moving coil, a switch for making andbreaking said circuit, and means actuated by the moving coil of thebreaker for actuating the switch, the said means being arranged todefinitely and periodically open and close the circuit, the interval oftime in which the circuit isclosed being of less duration than the timeit is open.

17 The combination with an electrical measuring instrument, of acircuit-breaker for maintaining a periodic opening and closing of acircuit comprising a contact for closing an electric circuit, a coil ofconstant potential and a cooperating member therefor controlling theaction of the contact, and means for retarding the closing of thecontact so that the interval of circuit-closure is of less duration thanthe interval during which it is open.

In witness whereof I have hereunto set my hand this 14th day of March,1898.

ELIHU THOMSON.

Witnesses:

' DUGALD MoKILLoP,

JOHN MOMANUS.

